(a) Field of the Invention
The present invention relates to a random access method and device in a mobile communication network.
(b) Description of the Related Art
Machine-to-machine (M2M) communication may be defined to be ubiquitous communication between machines so as to perform various operations such as sensing, processing, decision making, or acting on decisions. The biggest difference between the M2M communication and human-to-human (H2H) communication is a reduction in management of persons in a communication lifecycle.
However, new applications are generated among different types using the M2M technology because of gradually increasing automation, which has substantially increased the number of devices (terminals) to which the M2M technology is applied. The devices are used for various applications. Some devices are used in applications for an emergency situation thereby requiring a very high success probability and a very short access delay time. Some devices are used in applications for fixed scheduling thereby requiring somewhat high success probability and a relatively short access delay time. Some devices have a relatively low limitation compared to other applications so a low success probability and a long access time may be applied.
However, regarding a present mobile communication network, many devices share sixty-four random access channel (RACH) preambles and use the same irrespective of applications. Further, priority information may be provided to the devices in the network.
In addition, the management of massive connectivity (MC) for satisfying quality of service (QoS) requirements of various applications operable in the devices has become an important issue.
Therefore, when the number of devices simultaneously attempting to access the network is greater than an amount of available radio resources, an overload is generated and a failure probability of network access is increased so a method for solving this problem is required.
Further, the H2H devices require high access success probabilities and short access delay times. However, the M2M devices allow low access success probabilities and long access delay times depending on the applications. In the mobile communication network, the H2H devices share sixty-four RACH preambles to the maximum with the M2M devices. The number of M2M devices is greater than the number of H2H devices so the M2M devices deteriorate performance of the H2H devices.
Therefore, in a congested condition in which there are many devices (terminals) simultaneously attempting to access the network, a prerequisite method for dynamically controlling the random access attempt based on a network load, separating RACH resources of the H2H devices and RACH resources of the M2M devices, and maintaining performance of the H2H devices is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.